Telephone system.



J. M. LATIMER. TELEPHONE SYSTEM. APPLICATION FILED SEPT.14,1908.

927,41 4. Patented July 6, 1909.

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TELEPHONE SYSTEM.

YAPPLIUATION FILED 512F114, 1908.

927,414. Pate nted July 6, 1 909.

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c/Ohl? M orrc's Lafimer UNITED ELTENT OFFICE.

JOHN MORRIS LATIMER, OF FLUSHING, NEW

YORK, ASSIGNOR TO CONSOLIDATED FIRE ALARM COMPANY, OF NEW YORK, N. "'1 A CORPORATION O1! NEW YORK.

TELEPHONE SYSTEM.

Original application filed April 21, 1900, Serial No. 13,762.

Serial No.

Specification of Letters Patent.

Patented July 6, 1909.

To all whom it may concern:

Be it known that I, JOHN M. LATIMnn, citizen of the Unitedv States, residing at Flushing, Queens county, New York, have invented certain new and useful Improvements in Telephone Systems, of which. the following is a full, clear, and exact description.

This invention is an improvement in telc phone systems and has for its object to utilize existing telephone lines for the transmission of subscribers telephone messages, and also other telephone messages, in such a manner that the two classes of messages can be transmitted simultaneously without interfering with one another. In other words the leads of the telephone subscribers circuits which come together in an exchange are used for two distinct and. independent classes of service, one a subscribers exchange service and second. a service independent thereof.

This application is a division of my application Serial No. 13,762, filed. April 21, 1900, which application shows a system in which the subscribers circuits are used for transmitting alarm signals, as well as in dependent telephone signals, and the alarm transmitting and. receiving apparatus are, therefore, shown and described in connection. with the subject matter here claimed in order that the possibilities of the invention here claimed may be more comp rehensivoly set forth.

In the system as herein disclosed, neutral relays are placed in the leads of the telcp honecircuits at the exchange to repeat the signals from the telephone-circnits to the circuits extending to the alarm-receiving headquarters. The telephone lines are also utilized for transmitting answering signals to the local points from which the alarm signals are transmitted, and to establish direct telephone connection between the points from which the alarm. signals are transmitted and the alarm receiving headquarters. The construction is such that these objects are attained. without interfering with the ordinary telephone exchange service over the lines.

The telephone circuits radiate from a telephone exchange to various sets of telephone subscribers apparatus, and these circuits are primarily constructed for the purpose of connecting the telephone subscribers with the exchange. The setsof alarm transmitting apparatus are connected to the lines of the telephone circuits which are most convenicntly reached, and the system is such as not to interfere with the telephone exchange service, or be interfered with by the tele 'ihonc exchange service. The construction is also such that the telephone subscribers service is not interrupted at any time or disturbed, except at the actual instant of sending signals. The signals from the sets of local alarm transmitting apparatus are received by alarm repeating relays at the telephone exchange. These relays are so constructed that they will respond. to signals from the sets of local alarm apparatus, but will not respond to the telephone subscribers signaling and talking currents.

The alarm signal currents may or may not affect the telephone signal receiving devices at the switch-board, but if they do, their special character will be easily recognized by the exchange operators, and not be mistaken for telephone subscribes calls. The signals are automatically transmitted by the alarm repeating relays in the telephone circuits to the alarm receiving headquarters, and their transmission consequently independent of any attention from the exchange operators, and, therefore, not subject to the danger of oversight or delay on their part, as would be the case if they were required. to repeat the signals. 'llhe cons-t .z-tion also is such. that it is immaterial whether or not the telephone circuit is in. use for ciiinycrsaticn and connected to another telephone circuit at the exchange, when called. upon for the transmission of alarm signals. it important to be independent of this condition, because, when the telephone circuit is connccted to another exchange by means of a trunk connection, the telephone subscribers clearing-out signal would, according to usual telephone practice, be out out at the local exchange, and only be received in the exchange at the long distance point, in event that the distant subscriber is the calling subscriber, and, therefore, if an alarm signal depended for indication upon the local exchange, thcrc would be no meals, under these conditions, of indicating it at the local exchange, and it would go to the distant exchange instead, which might be in another city.

In the accompanying two sheets of drawings, which form a part of this specification,

Figure 1 is a diagram showing an alarm system applied to a common battery exchange in which the alarm transmitting sets and the alarm headquarters are in communication through a duplex telephone system. Fig. 2 is a diagram showing an out-door police telegraph and telephone system, an out-door public fire alarm telegraph and telephone system, and an in-door automatic or manual private alarm service, all applied to a common battery exchange, as in Fig. 1.

The system as shown in Fig. 1 will first be described: The telephone subscribers sets 1, of which but one is shown, are connected to a common battery telephone exchange by the battery leads 2 and grounded leads 3, which form the telephone subscribers circuits and connect the subscribers sets with the open terminal spring-jacks 4 and the grounded common battery 5. The battery leads are connected through line signal relays 6 to the line terminal of the common battery, and the grounded leads are connected to the grounded terminal of the common battery. The line signal relays close circuits through line signal lamps 7. In front of the spring-jacks for each circuit are test rings 8, which are connected through an exchange cut-oil relay 9 to the grounded terminal of the common battery. The insertion of the usual exchange cord circuit plug in the jack of a telephone subscribers circuit, connects the test-ring with the live terminal of the battery, and with the cut-off relay shifts the connections of the grounded lead of the telephone subscribers circuit to ground through a repeating coil in the cord circuit, and shifts the connections of the battery lead of the telephone subscribers circuit in the battery through another repeat ing coil in the cord circuit. In the cord circuit are placed signal lamps which light on the cessation of battery current. Such a cord circuit is illustrated in United States Letters Patent to H. M. Crane, No. 520,745, dated Mar. 7, 1899.

The alarm system and the manner in which the telephone circuits are utilized for the transmission of alarm signals will now be described. At convenient points within the territory covered by the exchange are sets of local alarm transmitting apparatus each consisting either of a signaling wheel 10 and mechanism for operating it manually or otherwise, or a telegraph key 11. Each of these is connected to the battery lead of any telephone subscribers circuit, which may be conveniently near and eil'ects connection between the lead and the ground. The telephone circuits to which such connections are made have, in both leads at the exchange, alarm repeating relays 12, which are neutral relays, with the coils balanced in the two leads. All currents, which are used in signaling and telephoning between telephone subscribers and the telephone exchange, course through both leads and both coils equally, but oppositely around the relaycore, thereby neutralizing each other, and, hence, do not ailect the relay. But when a contact is made by the alarm transmitting apparatus between the battery lead of the telephone circuit and the ground, the common battery current will flow through one coil only of the relay and it will attract its armature. Each relay controls contacts 13, which are in multiple in an alarm transmitting circuit 14. The closure of the contact at any relay, therefore, closes the alarm transmitting circuit.

In series with each relay contact is a coil of an automatic cut-out switch magnet 15 and a slow acting cut-out switch 16 which is con trolled by the cut-out switch magnet and opened when the magnet is fully energized. The core of each of these magnets, especially at the pole pieces, is surrounded with copper sleeves so that the magnet will magnetize slowly and will not attract its armature and open the alarm transmitting circuit until after a short interval. The cut-out switch magnet is also made to respond slowly to current by providing it with two armatures so adjusted that the one controlling the contact will not be attracted to the core until the other has been attracted to the core, and has thereby strengthened. the magnetic circuit. Between the closure of the alarm transmitting circuit at the relay and the opening of this circuit by the cut-out switch there is sufficient time to send an impulse such as is requisite in sending a signal. Because of the construction above indicated, this cutout switch operates whenever currents come into its coil and remain for a length of time, consequently in event of any current coming onto a line, which would operate its alarm repeating relay, and remaining on, this cutour switch magnet will operate and open that branch of the alarm transmitting circuit which is through the relay contact made by the alarm repeating relay, so that signals received 011 other alarm repeating relays can be repeated on this alarm transmitting circuit. The purpose of this cut-out switch is, therefore, to prevent the complete disabling of the entire alarm system through the individual disabling by the continuous grounding of, or the presence of a foreign current in, any one of the telephone circuits which is utilized for transmitting alarm signals. The cut-out magnet on operating and opening the alarm transmitting circuits, effects the closure of a contact 17 of a circuit through its coils and the contact of the neutral relay. It, therefore, remains energized as long as the relay remains energized, and prevents any permanent closure of the alarm transmitting circuit at the relay. Upon the cessation of the current which rendered the individual alarm relay inoperative, the cut-out magnet will release its armature and the alarm transmitting circuits will be restored to control by the neutral relay in the circuit which was disabled.

The alarm transmitting circuit 14 is wholly within the exchange and is preferably a normally open circuit. It is supplied from the common battery and contains a relay 18 which controls a contact in a second transmitting circuit 19 extending to the relay 20 at the alarm receiving headquarters. In order to save wires, the telephone leads 21 between the headquarters and the exchange areusedin parallel for the transmission of these signals by a duplex arrangement, which isnon-interfering with the telephone circuit. Branches from both leads at the headquarters are ledthrough impedance coils 22 and joined to the lead of the circuit 19. Branches from both leads at the exchange are led through impedance coils 22 and joined to the leads of the circuit 19. The circuit is from the common battery through the contact of the relay 18 to the point of juncture of the branches from the telephone leads at the exchange, thence in parallel over these branches and the impedance coils in the exchange branches, the telephone leads, the branches from the telephone leads andthe impedance coilsto the point of 'uncture at theheadquarters, thencethroug the relay 20 and telegraph key 23 to ground, and back to the common battery, thus completing the circuit. The relay 20, on operating, closes a local circuit through a local battery 24, and an alarm receiving apparatus consisting of a register 25 and bell 26. The transmitter and primary coil of the telephone set 27 at the headquarters is also in this circuit.

The leads from the receiver and secondary coil of the telephone set are carried to repeating coils 28 on the cores of the neutral relays in the telephone subscribers circuits at the exchange. that current, which may be induced in any one of the coils, will also flow in the others.

As shown in the drawings, they are connected. by placing them 1n serles 1n the circuit of the telephone at the headquarters. As the neutral relays are balanced with respect to the subscribers circults, currents 1n the repeating coils will not repeat to these circuits. 1

These coils are all connected, so

series. Consequently, the branches from the telephone subscribers circuit and the branches from the telephone circuit between the alarm headquarters and the exchange, although they shunt these circuits, do not impair their efliciency in the transmission of talking currents. The circuits in parallel are carefully balanced, so that they will neutralize each other with respect to the telephone subscribers apparatus. The condensers in the branches of the telephone subscribers circuit prevent the closure of this circuit through them to continuous currents, and hence do not afford a closed circuit to the common battery. The repeating coils 28 are wound with two parallel wires, and after Winding one wire is connected in series with the other to reduce the impedance.

The sets of local alarm telephone apparatusareconstantly connected through the neutral relays, and repeating coils with the telephone set at the alarm headquarters, and with each other, it being necessary only to remove the receivers from the hooks to place them in communication. As the local battery circuit through the telephone transmitter at the alarm headquarters is closed when the bell is sounded, it follows that the sounding of the bell at the headquarters can be heard in any telephone of the sets of local alarm apparatus, and a person, when sending an alarm, can, by first listening in the telephone, ascertain whether or not he will interfere with a user of the system between any other local alarm apparatus and the headquarters. By continuing to listen while signaling, he can also ascertain whether or not his signals are properly sounded at the headquarters. The alarm transmitting apparatus and the alarm receiving apparatus in each set of local alarm apparatus are in different circuits, although they may use the same leads, and are independently operating, except for their connection through the relays and circuits at the telephone exchange and at theheadquarters. The operator at the headquarters can acknowledge and answer the signals, either by telephone or by means of a telegraph key. This key, when opened, sounds the bell at the headquarters, the sound of which is transmitted over the telephone circuits to the local alarm apparatus.

The system as shown in Fig. 2 will now be described. This shows a common battery telephone exchange, as in Fig. 1, with live complete telephone subscribers sets and circuits connecting them with the exchange. The telephone circuits are utilized for three classes of alarm service, and the alarm signals in each class are received in separate alarm transmitting circuits at the exchange. These three classes of service are as follows: (a) An out-door public or munici al fire alarm service for use by policemen, 'remen and others,

comprising sets of local fire alarm apparatus each consisting of automatic or manually operated signaling wheels 10 a telegraph key 11" and a telephone set 30 for sending fire alarm and special signaling to and affording direct telephone communication through relays 12 and 18, telegraph circuits 14 and 19 and telephone circuits 21 with the headquarters apparatus, comprising the relay 20, register 2' bell 26 and telephone set 27; (b) an out-door public or municipal police service comprising sets of local police signal apparatus, each consisting of a manually operated signaling wheel 10, a telegraph key 11 and a telephone set 30" for sending signals to and affording direct telephonic communication through relays 12 and 18 telegraph circuits 14 and 19 and telephone circuit 21 with the police heaquarters apparatus, comprising the relay 20 register 25", bell 26 and telephone set 27 (c) an n-door automatic or manual private alarm service for sending distinctive signals by means of a local alarm set with a signaling wheel 10, through relays 12 and 18 and through circuits 14 and 19 to a private fire, police or other alarm receiving headquarters comprising the relay 20, register 25, and bell 26.

The apparatus and circuits for the first two of the three foregoing classes of service are substantially identical in their arrangement and operation, with the apparatus and circuits described in connection with Fig. 1, and the apparatus and circuits for the third class of circuits differs from the system of Fig. 1 chiefly in the omission of the telephone sets. The sets of local fire alarm apparatus differs from the sets of local police signaling apparatus in that the former is provided with mechanism for rotating the signaling wheel a number of times, and thereby repeating the signal, while the mechanism of the police signaling apparatus imparts but one revolution to the signaling wheel at each operation.

In the diagram, the sets of local out door public fire alarm apparatus are connected to the first and third telephone subscribers circuits, the sets of local out door police signaling apparatus are connected to the second and fourth telephone subscribers circuits, and the signaling wheel for the in door automatic or manual alarm apparatus is connected through the fifth telephone circuit. Additional sets of local police, fire and other alarm apparatus are connected to additional telephone circuits as may be required. The sets of local out door fire alarm apparatus and the sets of local police signaling apparatus may be entirely distinct and the sets located wherever they will be most convenient. But wherever it is desirable to have them near each other, they may be conveniently housed. in the same box or casing, as shown in the sets of fire alarm apparatus connected to the first telephone circuit and the set of police signaling apparatus connected to the second telephone circuit. When this is done, one telephone set 30 will serve for both, a switch 31 being provided to shift the telephone connection to either class of service. But one of the local stations of the in-door automatic service is indicated in the diagram. Two signaling wheels 10 and 10 are shown, and are operated by the same mechanism, which may be such as is shown in connection with the municipal fire alarm service. One of the wheels connects one of the leads of the telephone circuit to ground, and the other connects the other lead to ground. It is only necessary that the lead which is connected to the same common battery at the exchange should be grounded, and the object of the other wheel is to guard against the local alarm set being rendered inoperative by a transposition of the telephone wires at any point between the point of connection of the local set and the exchange battery. The wheels are preferably arranged so that both leads will be connected to ground at the same moment.

The signals from the indoor automatic service are received at the exchange in the circuit 14; and repeated by a relay 18 to the private alarm receiving headquarters. A register 32 is also connected with this re lay, so that the signals will be recorded at the exchange. A second relay 83 is also placed in the circuit 14, and controls a contact in the municipal fire alarm circuit. But this contact is normally short circuited by an automatic switch 84., so that the first automatic alarm signal will not be repeated onto the municipal alarm circuit, for such first signals are usually local trouble or test signals, and their indication at the fire headquarters would be objectionable to the fire departments. The automatic switch is in the form of a contact wheel, and is connected to a gear train, which is released for a limited time by a magnet 35 in the circuit 14. This mechanism, whenever started, leaves the switch closed for a time corresponding to the time taken by the signal wheels for their first revolution, and then opens the switch, so that all following sig nals of the same alarm will pass to the innnicipal fire head quarters. When the mechanism stops, it again closes the switch, so that subsequent trouble or test signals on any of the circuits of this class will be cut out from the municipal fire headquarters.

VJ hat I claim is:

1. The combination of sets of telephone subscribers apparatus, a telephone exchange, telephone subscribers circuits connccting the sets of telephone subscribers apparatus with the telephone exchange, sets of local alarm telephone apparatus, circuits including the sets of local alarm telephone apparatus, each of which has balanced branches in parallel over the leads of a telephone subscribers circuit, repeating coils which are connected to both leads of the telephone subscribers circuit at the telephone exchange, so that they will be responsive to currents which flow through the telephone subscribers leads in parallel and not to the telephone subscribers signaling and talking currents, and connections between the repeating coils at the exchange, substantially as described.

2. The combination of a telephone subscribers apparatus, a telephone exchange, a telephone subscribers circuit connecting the telephone subscribers apparatus with the telephone exchange and 0 en at a condenser in the telephone subscribers apparatus, a common battery in the telephone subscribers circuit at the exchange, alocal alarm telephone apparatus, a circuit containing the local alarm telephone apparatus which has balanced branches in parallel over the leads of the telephone subscribers circuit, condensers in branches of the circuits for the local alarm telephone apparatus, and coils which are so connected to both leads of the telephone subscribers circuit that they will be responsive to currents which flow through the telephone subscribers leads in parallel and not to the telephone subscribers signaling and talking currents, and telephone connections to said coils, substantially as described.

JOHN MORRIS LATIMER.

Witnesses:

ROBERT D. WEST, L. CHARLES PELTZ. 

